Introduction

CT scans are preformed frequently in the ED setting to evaluate a

variety of clinical scenarios. Traditionally most of these scans are

performed with intravenous and oral contrast except for the evaluation

of renal colic. However there is mounting evidence that oral contrast

may not increase the accuracy of these studies and may actually

degrade the study in a number of scenarios. 1-3

Purpose

In this study, we evaluate the benefits and pitfalls of not using oral

contrast in an emergent setting. We analyze the impact of

discontinuing oral contrast on patient care in the ER, taking into

account the time savings and monetary savings, as well as

acceptance by both radiologists as well as clinicians.

Use of Oral Contrast during CT scans: Current

literature review

Prospective study of 100 emergency department (ED) patients with

abdominal pain where patients were scanned without oral contrast and

then with oral contrast. Only 2 cases out of 100 were discrepant. 4

In the case of appendicitis, a meta-analysis of 23 studies showed

similar sensitivity (95% vs. 92%), specificity (97% vs. 94%) and

accuracy (97% vs. 89%). Other studies showed that diagnostic

confidence was not hindered.2,6

The ACR Appropriateness Criteria®, evidence-based guidelines

formulated by expert review panels, state the following:

In cases of right lower quadrant pain, use/ non use of oral or rectal

contrast does not change accuracy of the study.3,6,8

Oral contrast should not be used for evaluating suspected small

bowel obstruction and the IV contrast makes the biggest

contribution.2,7

Do we really need oral contrast to

make the diagnosis?

The Benefits and Potential Pitfalls of Lack of Oral Contrast on CT in the Emergent Setting

G K Spanos, M Balouch, S Reddy, D R Radin, S Palmer, S Swadron, V A Duddalwar

Department of Radiology, University of Southern California, Los Angeles, California 90033

Results:

We calculated the difference between time ordered and the time the study was started on our PACS.

There was only one case where the reading radiologist felt that oral contrast may have added to the diagnostic

confidence• In Feb 2010, when all patients received oral contrast, out of 256 patients, the average time it took was 3 hours and 3 minutes.

• In March 2010 when patients didn’t receive oral contrast, out of 304 patients, the average time was 2 hours and 44 minutes.

• This showed a savings of 19 minutes.

USC_____________

_____________

b b

a a a

c

c

References:1. ACR Appropriateness Criteria (2010), Acute Abdominal Pain and Fever or Suspected Abdominal Abscess. Amer. Coll. of Radiology. Retrieved November 15, 2010, from

http://acsearch.acr.org/.2. ACR Appropriateness Criteria (2010), Suspected Small Bowel Obstruction. Amer. Coll. of Radiology. Retrieved November 15, 2010, from http://acsearch.acr.org/.3. ACR Appropriateness Criteria (2010), Right Lower Quadrant Pain – Suspected Appendicitis. Amer. Coll. of Radiology. Retrieved November 15, 2010, from http://acsearch.acr.org/.4. Lee SY, Coughlin B, Wolfe JM, Polino J, Blank FS, Smithline HA. Prospective comparison of helical CT of the abdomen and pelvis without and with oral contrast in assessing acute

abdominal pain in adult emergency department patients. Emerg Radiol. 2006;12:150-157. Epub 2006 Apr 21. 5. Anderson BA, Salem L, Flum DR. A systematic review of whether oral contrast is necessary for the computed tomography diagnosis of appendicitis in adults. Am J Surg.

2005;190:474-478. 6. Anderson SW, Soto JA, Lucey BC, et al. Abdominal 64-MDCT for suspected appendicitis: the use of oral and IV contrast material versus IV contrast material only. AJR 2009;193

:1282 –1288 7. Megibow AJ, Balthazar EJ, Cho KC, Medwid SW, Birnbaum BA, Noz ME. Bowel obstruction: evaluation with CT. Radiology 1991; 180(2):313-318.8. Maglinte D, Herlinger H, Turner W, Kelvin F. Radiologic management of small bowel obstruction: a practical approach. Emerg Radiol 1994; 1994(1):138-149.

Potential Benefits and Pitfalls of No Oral Contrast

Benefits: a) Saves at least 90 minutes (time to opacify bowel)

b) Increases patient compliance

c) Increases ER throughput, by providing results to ER more rapidly

d) May increase the accuracy of study because:

Oral contrast may obscure masses, or hematomas2

Oral contrast may give a false idea of level of obstruction2

Pitfalls: a) Limited evaluation for suspected fistulas

b) Limited evaluation for suspected postoperative leaks

The PlanStarting March 1st 2010, NO ORAL CONTRAST was used for CT

scans of the abdomen and pelvis requested from the LAC + USC

Emergency Department, with the exception of ruling out fistulas.

Method:A retrospective review of data was performed after the study plan was approved by the local institutional review

board.

Data was reviewed from the Hospital and Radiology Information Systems as well as the PACS

Data sets were:

a) Patients who had a CT scan of the abdomen/pelvis WITH oral contrast in the month prior to the new

institutional policy (Feb. 2010).

b) Patients who had a CT scan of the abdomen/pelvis WITHOUT oral contrast in the month prior to the new

institutional policy (Mar. 2010).

Exclusion criteria included “trauma” and “rule-out fistula” on the initial ER requisition.

The waiting times between the physician placing the order and the patient obtaining the scan were obtained.

SBO without oral contrast

Appendicitis with oral contrast Appendicitis without oral contrast

Diverticulitis with oral contrast

SBO with oral contrast

Diverticulitis without oral contrast

Median = 2 hours and 39 minutes

Average = 3 hours and 3 minutes

Median = 2 hours and 20 minutes

Average = 2 hours and 44 minutes

Conclusion:

In our experience at the LAC+USC ER, not using oral contrast saved an average of 19 minutes. While more

time could potentially be saved, factors such as high demand on imaging and patient transport resources limit the

time saved currently.

Performing studies without oral contrast saves about an average of $25000-$30000 a year just in terms of the

cost of oral contrast. However cost of the time savings on the management of the patient in the ED have not been

calculated.

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